Years participated in RESESS:
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Academic Affiliation: University of Texas at San Antonio
Research Mentor: Stephanie Higgins
Communications Mentor: Keith Jennings
Jose Silvestre is currently a geoscience major at the University of Texas at San Antonio. His passion for the geosciences was sparked when his love for the outdoors led him to participate in a wild-cave tour. His interest in karst morphology led him to his current focus in fluvial geomorphology. For his RESESS project, Jose utilized modeling techniques to determine how India’s National River Linking Project will affect sediment transport to the Ganga-Brahmaputra-Meghna (GBM) Delta. Because suspended sediment deposition is crucial for the GBM to compensate for sea level rise, Jose’s results may have impacts on future policy making.
Modeling Sediment Transport to the Ganga-Brahmaputra-Meghna Delta
India’s National River Linking Project (NRLP) will transfer approximately 174 Bm3/y of water from the mountainous, water-rich north to the water-scarce south and west. Although there are many short-term benefits of the NRLP, such as decreased flooding during the monsoon season and increased water resources for irrigation, long-term consequences may include decreased sedimentation to the Ganga-Brahmaputra-Meghna Delta (GBM). Currently the GBM has a vertical aggradation rate of approximately 1-2 cm/y and is able to compensate for a global mean sea level rise of 3.3 ± 0.4 mm/y. However, Bangladesh and the GBM stand to be geomorphically impacted should the aggradation rate fall below sea level rise.
This study better constrains influences of anthropogenic activities and sediment transport to the GBM. We employ HydroTrend, a climate-driven hydrological and sediment transport model, to simulate daily sediment and water fluxes for the period 1982 – 2012. Simulations are calibrated and validated against water discharge data from the Farakka Barrage, and different ways of delineating the Ganga Basin into sub-catchments are explored. Preliminary results show a 47% difference between simulated and observed mean annual water discharge when using basin-averaged input values and only a 1% difference for the base-case scenario, where proposed dams and canals are not included. Comparisons between the canals simulation (proposed NRLP included) and validation data suggest a 60% reduction in sediment load. However, comparison between the base-case simulation and the canals simulation suggests that India’s water transfer project could decrease sediment delivery to the GBM by 9%. Further work should investigate improvements in the agreement between base-case simulation and validation data.